Question

Aestivation in the flower of Calotropis is,
(A) Twisted
(B) Imbricate
(C) Valvate
(D) Vexillary

Answer 1

Hint: Aestivation is the term used for the positional arrangement of the parts of the flower within a flower bud before it gets opened. Calotropis has adjacent edges abutting rather than overlapping.

Complete answer: The aestivation in corolla (petals) of Calotropis is valvate. In this type, petals are arranged in contact on margins without overlapping. While others are twisted, here, regular overlapping occurs like in china rose. In the imbricate, irregular type of overlapping exist like in Cassia. In vexillary, the larger ones overlap the inner ones, like in pea. Custard apple and Brassica also show valvate aestivation in corolla. Other than these, Tulip, Asparagus, Colchicum, Petunia, mustard and tobacco have valvate aestivation. Calotropis is a genus of flowering plants in the family Apocynaceae. They are
commonly known as the milkweeds because of the latex they produce. Calotropis species are
considered as the common weeds in some parts of the world. The flowers have a fragrance and are
often used in making floral tassels in some mainland southeast Asian cultures. ‘Madar’ or ‘mader’ is a term used for the fibres of these plants. These species are especially found in abandoned farmland. The milky exudation from the plant is a corrosive poison.
Hence, the correct answer is option C.

Note: Calotropis species are very poisonous plants; a compound called calotropin is found in latex, which is more toxic than the strychnine. This is used as an arrow poison, cattle poison, rarely used for suicide and homicide and mostly as an accidental poison. Cattle too stay away from the plants because of the taste which is unpleasant and their content of cardiac glycosides.